Confidence is something that is beneficial in all walks of life, unless it becomes complacency or arrogance. In trying to forge a career in a creative industry this is especially important, as there can be very long periods in the wilderness while striving to succeed. It is the same story for most people in music and films.
Like a band that spends its own money touring and recording when the chance of a pay day is quite slim, a similar feeling can creep in when making movies. Spending money attending meetings, spending time on script development and also emotional investment into a project all can take their toll, resulting in stress, uncertainty and doubt.
I imagine the answer to this question is different for everyone. For me, it is the need to tell stories, to entertain and to make people believe the unbelievable. Because of cinema, millions of people have all been united in laughing, crying and feeling other emotions in a dark room. I thoroughly believe that a film has only truly failed when a viewer leaves feeling numb. The final reason, is wanting to give back to audiences what cinema has given to me.
The time after a project is the main time when doubt begins to try to grab hold. This is because as a crew, everyone bonds and comes together for the sole purpose of making the film as good as it can be, and then after spending ridiculously long hours together every day, it stops. There is also the fact that once the project is done, there may be another battle to get the next job/ commission.
I think at the moment it is that time when a little bit of a reality check is occurring, constantly reminding myself that for every Jerry Bruckheimer there hundreds who pedalled ideas and never got one made. It happens every now and again, haunts you for a day and then leaves.
But I wouldn't change these feelings for the world, as with every arrogant or cocky person I meet in this industry, I feel assured that this thought process acts to keep me grounded and appreciate when things are going well.